I picked up some NutriPak 16-16-16 Controlled Release Fertilizer For Fruit and Nut Trees, 3 Year packs for my apple trees ranging from 1+ to 4+ years of age. They are purple haze, johnny come lately, along with bunches & bunches of red crabapple. The pack mention one per 1" tree diameter...is it ok to bury one packet as directed (6-8 inches deep near roots) if trunk diameter is less than one inch?

Can these packets be used on new seedlings at time they are planted or is it best to wait a full season before introducing a a fertilizer pak?